Multi-through hole testing plate for high throughput screening

ABSTRACT

A method for holding samples for analysis and an apparatus thereof includes a testing plate with a pair of opposing surfaces and a plurality of holes. Each of the holes extends from one of the opposing surfaces to the other one of the opposing surfaces. The holes are arranged in groups, where each group has at least two rows and two columns of holes. The groups are arranged in sets, where each set has at least two rows and two columns of groups. To analyze samples, at least one of the opposing surfaces of the testing plate is immersed in a solution to be analyzed. A portion of the solution enters openings for each of the holes in the immersed opposing surface. Once the holes are filled with solution, the testing plate is removed and is held above a supporting surface. Surface tension holds the solution in each of the holes. The solution in one or more of the holes is then analyzed and the solution in one of these holes is identified for further study. The location of the identified solution is marked based upon its location within a particular set and group of holes.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/276,179, filed Oct. 18, 2011, which is a continuation ofU.S. patent application Ser. No. 10/969,104, filed Oct. 20, 2004, whichis a division of U.S. patent application Ser. No. 10/223,893, filed Aug.20, 2002, which is a continuation of U.S. patent application Ser. No.09/970,578, filed Oct. 4, 2001, which is a continuation of U.S. patentapplication Ser. No. 09/528,085, filed Mar. 17, 2000, which is acontinuation-in-part of prior U.S. patent application Ser. No.09/471,852 filed Dec. 23, 1999, which in turn is a continuation of U.S.patent application Ser. No. 09/272,122, filed Mar. 19, 1999, each ofwhich are herein incorporated in their entireties by reference.

FIELD OF INVENTION

This invention is related generally to a testing apparatus and, moreparticularly, to a multi-through hole testing plate for high throughputscreening.

BACKGROUND OF THE INVENTION

Prior testing apparatuses have consisted of a testing plate with a pairof opposing surfaces and a plurality of wells. The wells extend in fromone of the opposing surfaces, but do not extend through to the otheropposing surfaces. The wells are used to hold samples of solution to beanalyzed.

Although these testing apparatuses work there are some problems. Forexample, the wells in these testing apparatuses are difficult to fill.Special delivery systems, such as large pipette systems, are needed tofill each of the wells with samples of solution. These special deliverysystems are often expensive and difficult to operate. As a result, theoverall cost of the testing procedure is increased.

Another problem with these prior testing apparatuses is with theirconstruction. The bottom of the wells in these testing plates need to betransparent so that light can be transmitted through the samples duringtesting. However, the rest of the testing plate needs to be constructedof a non-transparent material. The construction of a testing apparatuswith these characteristics is difficult and expensive.

Yet another problem with these prior testing apparatuses is with theoperator locating a particular well in the testing apparatus. Typically,these testing apparatuses each include large numbers of wells which areequidistantly spaced apart. As a result, locating a particular wellwithin the large number of wells is difficult.

Accordingly, there is a need for an improved testing apparatus for highthroughput screening.

SUMMARY OF THE INVENTION

A method for holding samples in accordance with one embodiment of thepresent invention includes several steps. First, a testing plate with apair of opposing surfaces and a plurality of holes is provided. Each ofthe holes extends from one of the opposing surfaces to the other one ofthe opposing surfaces. Next, at least one of the opposing surfaces ofthe testing plate is immersed in a solution to be analyzed. A portion ofthe solution enters openings for each of the holes in the immersedopposing surface and any gases in the holes escape through openings foreach of the holes in the other opposing surface. Next, the testing plateis removed from the solution. Surface tension holds some of the solutionin each of the holes. The opposing surfaces of the testing plate arethen held above a supporting surface and the solution held in at leastone of the holes is analyzed.

A method for identifying the location at least one sample of a solutionin accordance with another embodiment of the present invention includesseveral steps. First, a testing plate with a pair of opposing surfacesand a plurality of holes is provided. Each of the holes in the testingplate extend from one of the opposing surfaces to the other one of theopposing surfaces. The holes in the plate are arranged in groups. Eachof the groups comprises at least two rows and two columns of holes. Oncea testing plate has been provided, solution is loaded into the holes andis then analyzed. Based on this analysis, the solution in at least onehole is identified for further study. The location of the identifiedhole is marked based upon the group in which the hole is found.

A method for screening a sample in accordance with another embodiment ofthe present invention includes several steps. First, a solution of thesample is prepared for screening. Next, a testing plate with a pair ofopposing surfaces and a plurality of holes is provided. Each of theholes extends from one of the opposing surfaces to the other one of theopposing surfaces in the testing plate. Next, at least one of theopposing surfaces of the testing plate is immersed in a solution. Aportion of the solution enters openings for each of the holes in theimmersed opposing surface of the testing plate. Once the solution hasenter into the holes, the testing plate is removed from the solution andthe surface tension holds at least some of the solution in the holes.Next, the solution in one or more of the holes is analyzed.

An apparatus for holding samples of a solution with cells for analysisin accordance with another embodiment of the present invention includesa testing plate with a pair of opposing surfaces and a plurality ofthrough holes. Each of the holes extends from an opening in one of theopposing surfaces in the testing plate to an opening in the other one ofthe opposing surfaces and is sized to hold a plurality of the cells. Aportion of at least one of the opposing surfaces of the testing platewhere the holes are located is recessed so that the openings in thetesting plate are spaced in from the opposing surface.

An apparatus for holding samples for analysis in accordance with yetanother embodiment of the present invention also includes a testingplate with a pair of opposing surfaces and a plurality of holes. Each ofthe holes extends from one of the opposing surfaces to the other one ofthe opposing surfaces. The holes are arranged in groups on the testingplate, where each of the groups comprises at least two rows and twocolumns of holes.

The method and apparatus for holding samples for analysis in accordancewith the present invention provides a number of advantages. For example,the present invention simplifies testing procedures. The samples ofsolution to be analyzed can be loaded into the testing plate by simplydipping or flooding one of the surfaces of the testing plate into thesolution. As a result, the present invention does not require the use ofa separate delivery systems for loading solution into the wells on thetesting plate.

The present invention also simplifies the construction of the testingapparatus. The testing apparatus merely needs one of the opposingsurfaces of the testing apparatus to be spaced away by additionalspacers or machined to create a recessed portion and then a plurality ofholes need to be drilled through the plate in the recessed portion.Unlike prior testing apparatuses, the present invention does not requireany special construction techniques to make the bottom of the wellstransparent because the holes extend all of the way through the plate.

The present invention also permits an operator to more easily identify aparticular hole filled with a sample for further analysis. Instead ofspacing the holes equidistantly over the testing plate, the presentinvention arranges the holes in groups of at least two columns and tworows of holes and arranges the groups in sets of at least two or more.The groups are spaced further apart then the holes within each group andthe sets of groups are spaced further apart then the groups are spacedapart. As a result, an operator can more easily identify a particularhole based upon which set, group, row, and column the hole is located inon the testing plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a multi-through hole testing plate in accordancewith one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the multi-through hole testing plateshown in FIG. 1 taken along lines 2-2;

FIG. 3 is a perspective, exploded view of another multi-through holetesting plate in accordance with the present invention between a pair ofevaporation plates;

FIG. 4 is a block diagram of a testing apparatus with a multi-throughhole testing plate in accordance with another embodiment of the presentinvention;

FIG. 5 is a top view of the multi-through hole testing plate inaccordance with another embodiment of the present invention;

FIG. 6 is a cross-sectional view of the multi-through hole testing plateshown in FIG. 5 taking along the lines 6-6;

FIG. 7 is a top view of a multi-through hole testing plate in accordancewith yet another embodiment of the present invention;

FIG. 8 is a top view of a testing plate assembly according to anembodiment of the present invention; and

FIG. 9 is a perspective view of the assembly of FIG. 8 shown in partialcut-away.

DETAILED DESCRIPTION

A testing apparatus 10 in accordance with one embodiment of the presentinvention is illustrated in FIG. 1. The testing apparatus 10 includes atesting plate 12 with a pair of opposing surfaces 14 and 16 (surface 16is shown in FIG. 2) and a plurality of through holes 18. The throughholes 18 are located in recessed portions 20 and 22 on each side of thetesting plate 12. The through holes 18 are also arranged in groups 24 ofat least two columns and two rows of holes 18 and in sets 26 of two ormore groups of holes 18. The testing apparatus 10 provides a number ofadvantages including simplifying the procedure for loading samples ofsolution S into the holes 18 in the testing apparatus 10, simplifyingthe construction of the testing apparatus 10, and making theidentification of a particular hole 18 filled easier for an operator.

Referring to FIGS. 1 and 2, the testing apparatus 10 includes thetesting plate 12 which in this particular embodiment is made of anon-transparent material, such as aluminum and polypropylene, althoughother types of materials, such as teflon, polystyrene, stainless steel,polyethylene, any metal or plastic, can be used. The testing plate 12could also be made of transparent materials, such as glass ortransparent plastic, when non-optical means are used for analysis, suchas analyzing the materials blotted on membranes.

The testing plate 12 includes the pair of opposing surfaces 14 and 16.In this particular embodiment, the opposing surfaces 14 and 16 aresubstantially planar, except where the recessed portions 20 and 22 arelocated, although the surfaces 14 and 16 could have other relationshipswith respect to each other. Each of the opposing surfaces 14 and 16includes one of the recessed portions 20 and 22 which are machined intothe testing plate 12, although other techniques for forming the recessedportions 20 and 22, such as by molding or adding spaces, can be used.When either of the opposing surfaces 14 and 16 of the testing plate 12rests on a supporting surface 28, the recessed portion 14 or 16 alongwith the plurality of holes 18 located in the recessed portion 14 or 16are spaced away from the supporting surface 28. If openings 30 and 32 tothe holes 18 contacted the supporting surface 28, then any solutions inthe holes 18 would drain out of the holes 18. In this particularembodiment, a ridge 34 if formed in each of the opposing surfaces 14 and16 by the recessed portions 20 and 22 which extends around the outercircumference of the testing plate 12. Although the holes 18 are spacedfrom the support surface 28 by a recessed portion 20 or 22 formed in thetesting plate 12, the holes 18 can be spaced from the supporting surface28 with other types of supporting structures, such as a bracket attachedto the testing plate which supports the testing plate 12 and holes 18above the supporting surface 28.

Referring to FIGS. 5 and 6, another testing apparatus 50 in accordancewith one embodiment of the present invention is illustrated. The testingapparatus 50 is identical to the test apparatus 10 shown in FIGS. 1 and2 except that the testing apparatus 50 does not include a pair ofrecessed portions. Instead, the testing apparatus 50 has a recessedportion 52 and a protruding portion 54. When the testing plate 51 isplaced on a supporting surface, the recessed portion 52 must be facingthe supporting surface so that the holes are spaced from the supportingsurface. Although one example of the testing apparatus 50 is shown, theopposing surfaces of the testing plate 51 could have otherconfigurations. For example, protruding portion 54 could be made flushwith the upper surface of testing plate 51.

Referring to FIGS. 1-3, the testing plate 12 also includes an optionalhandle 36 and an opening 38 on one side of the testing plate 12 toreceive one end of the handle 36, although other techniques forconnecting the handle 36 to the testing plate 12 can be used, such asconnecting the handle 36 with bolts. The handle 36 extends out from theside of the testing plate 12 and is used to maneuver the testing plate12 during loading and testing.

A plurality of through holes 18 are located in the testing plate 12. Theholes 18 extend from openings 30 in the recessed portion 20 of one ofthe opposing surfaces 14 to openings 32 in the recessed portion 22 ofthe other opposing surface 16. In this particular embodiment, the holes18 have a substantially cylindrical shape, although the holes 18 couldhave other shapes, such as a hexagonal cross-sectional shape or a coneshape. In this particular embodiment, each of the holes 18 has adiameter of about one millimeter and can hold about 5.5 microliters ofsolutions S and cells C, although the diameter, volume and number ofcells C each hole 18 can hold can vary as needed or desired. Thesolution S along with cells C in the solution S are held in the holes 18by surface tension as shown in FIG. 4. More specifically, the size ofthe holes 18 may need to change depending upon the solution S to beanalyzed and that solution's surface tension properties. For example asunderstood by one of ordinary skill in the art, a buffer solution mighthave different surface tension properties than a culture mediacontaining salt. There must be sufficient surface tension to keep thesamples of solution S in the holes 18.

One of the advantages of the present invention is that the testing plate12 is easy to manufacture. A plate having opposing surfaces can have anappropriate number of holes drilled there through. The plate can includeone or more recessed portions 20, 22, and the through holes can passthrough the recessed portion of the plate 12. Since the holes 18 extendall of the way through, there is no need for a transparent bottom ineach hole 18. Light transmitted into the holes 18 will pass throughduring testing. With prior wells, the testing apparatus also needed tobe non-transparent, but since the wells did not extend through theapparatus, the bottom of the wells needed to be made of a transparentmaterial to permit light to pass through the sample for opticalanalysis. Constructing these prior testing apparatuses was difficult andexpensive.

Referring to FIG. 1, the testing plate 12 has about two-thousand holes18 which extend through from one opposing surface 14 to the otheropposing surface 16, although the number of holes 18 can vary as neededor desired. To assist an operator in identifying a particular hole 18 inthis particular embodiment the holes 18 are arranged in groups and setsof holes 18. Each group 24 contains at least two rows and two columns ofholes 18 and each set 26 includes at least two rows and two columns ofgroups 24. In this particular embodiment, each group 24 of holes 18 hasfive rows and five columns of holes 18 and there are eighty groups 24 oftwenty-five holes 18 in this example, although the number can vary asneeded or desired. The holes 18 in this example are spaced about 1.5 mmapart between rows of holes 18 and between columns of holes 18 withineach group 24, although this distance can vary and the spacing betweenrows of holes 18 and columns of holes 18 within each group 24 can bedifferent as needed or desired. In this particular embodiment, each setof groups 24 includes two rows of groups 24 and ten rows of groups 24and there are four sets 26 which contain twenty groups 24 of holes 18each in this example, although the number can vary as needed or desired.The groups 24 within a set 26 in this example are spaced about 2.0 mmapart and the sets 26 of groups 24 of holes 18 in this example arespaced about 2.5 mm apart, although these distances can vary as neededor desired.

By arranging the holes 18 in sets 26 and groups 24, it is much easierfor an operator to identify a particular hole 18 in the testing plate 12and retrieve a particular sample. The sets 26 of holes 18 help theoperator identify the general area of the hole 18 and then the groups 24help the operator to begin to narrow down the location of the hole 18.The column and row of the hole 18 in each group 24 provides the preciselocation of the hole 18. The spacing between sets 26, groups 24, androws and columns are different to make it visually easier for anoperator to identify a particular hole 18. When the holes 18 are allspaced equidistantly apart, then it is more difficult to identify aparticular hole 18 and it is easier for an operator to lose his/herplace and select a sample from the wrong hole 18.

Although the holes 18 are arranged in groups 24 and sets 26 in testingapparatuses 10 and 50 to aid human operators, other arrangements for theholes 18 may also be used. For example, when the testing apparatuses areused by robotics, instead of human operators, the holes 18 can also bespaced equidistantly apart as shown in the embodiment of the testingapparatus 60 illustrated in FIG. 7. The testing apparatus 60 isidentical to the testing apparatuses 10 and 50 described and illustratedearlier except for the that the holes 18 are equidistantly spaced apart.

Referring to FIG. 3, the testing apparatus 10 may also include a pair ofoptional evaporation plates 40 and 42. The evaporation plates 40 and 42are each secured to the one of the opposing surfaces 14 and 16 of thetesting plate 10. The evaporation plates 40 and 42 are secured to thetesting plate 12 by bolts, clamps, or other mechanical means. When theevaporation plates 40 and 42 are secured to the testing plate 12 overthe recessed portions 20 and 22, the recessed portions 20 and 22 in theopposing surfaces 14 and 16 of the testing plate 12 still space theopenings 30 and 32 of the through holes 18 away from the evaporationplates 40 and 42. The evaporation plates 40 and 42 help to preserve thesamples of solution S in the holes 18 in the testing plate 12 fromevaporation and contamination.

Instead of a recessed portion in the plate 12, an assembly comprisingthe plate and evaporation plates can be provided with spacers betweenthe testing plate and the evaporation plates to space the openings ofthe through holes away from the evaporation plates. The evaporationplates could be provided with recesses portions in addition to, orinstead of, spacers between the testing plate and the evaporationplates. Any combination of recessed portions in the testing plate,recessed portions in the evaporation plates, or spacers can be used toprovide the spacing between the openings of the through holes and theevaporation plates.

According to an embodiment of the present invention, stackable testingplates are provided which may or may not have evaporation platesin-between testing plates. The stackable testing plates may be providedwith recessed portions or evaporation plates with recessed portions canbe provided between a stacked testing plate. Any combination of recessedportions in the testing plates, recessed portions in the evaporationplates, or spacers can be used to provide a stack of testing plateswherein each testing plate is spaced from the surface of an adjacenttesting plate, evaporation plate, or both.

One example of one application of the present invention will bediscussed with reference to testing apparatus 10 shown in FIGS. 1-4. Inthis particular example, cells C are mutagenized using ultraviolet,chemical mutagenesis, or other mutagenesis technology. The cells C aregrown to allow for segregation. Once the cells C have grown, the cells Care diluted to one cell C per ten microliters in a medium containing afluorgenic or chromogenic substrate. For purposes of this example, themedium with the cells C is referred to as the solution S. As a result,the cells will be randomly distributed in the holes 18 and many of theholes 18 will contain one or more cells C.

Although one example of preparing the solution S and cells C isdisclosed, other methods and techniques for preparing samples to be usedwith the testing apparatus 10 can be used as is readily understood byone of ordinary skill in the art.

Next, a testing plate 12 with a pair of opposing surfaces 14 and 16 anda plurality of holes 18 which extend from one of the opposing surfaces14 to the other one of the opposing surfaces 16 is provided. At leastone of the opposing surfaces 14 of the testing plate is immersed in theprepared solution S. The solution S enters openings 30 and 32 for eachof the holes 18 in testing plate 12 and any gases in the holes 18 mayescape through openings 30 and 32 at the opposite end of the holes 18.Alternatively, the testing plate 12 may be flooded with solution S sothat the solution S enters through the top opening 30 to each hole 18.

One of the advantages of the present invention is the ease with whichsolution S can be loaded into each of the holes 18. As illustrated inthe description above, all of the holes 18 in the testing plate 12 canbe loaded with samples of solution S in a relatively short period oftime and without any type of specialized solution delivery system. Priortesting apparatuses with wells required specialized solution deliverysystem, such as large pipette devices, to be able to load solution intoeach of the wells. These specialized solution delivery systems aredifficult to use and are expensive.

Once the solution S has been drawn into the holes 18, the testing plate12 is removed from the solution S. Surface tension holds the solution Sin each of the holes 18. In this particular embodiment, each hole 18 hasa diameter of about one millimeter and holds about 5.5 microliters ofsolution S and cells C as shown in FIG. 4, although the diameter andvolume of each hole 18 can vary as needed or desired for the particularapplication. The handle 36 can be used to manipulate the position of thetesting plate 12 during the above-described operations.

Once the testing plate 12 is removed from the solution S, the testingplate 12 can be placed on a supporting surface 28. Since the holes 18are located in a recessed portion 22 of the testing plate 12, theopenings 22 to the holes 18 are spaced from the supporting surface 28 sothat any solution S being held by surface tension remains in the holes18. A pair of evaporation plates 40 and 42 may be attached to theopposing surfaces 14 and 16 of the testing plate 12 to prevent thesamples of solution S in the testing plate 12 from evaporating orbecoming contaminated.

In this particular example, the testing plate 12 is then optionallyincubated at a controlled temperature of about 37° C. and a humidity ofabout 70%, although the temperature and humidity will vary based uponthe particular application. During the incubation, the cells multiplyand produce a protein of interest (the cells could produce an enzyme, anantibody, or a metabolite which could be of interest). The ability ofthe protein, such as an enzyme, to hydrolyze a substrate is analyzed,such as by measurement of fluorogenic or chromogenic groups liberated bythe hydrolysis.

Although one example of processing the samples of solution S in thetesting plate 12 is disclosed, other methods and techniques forprocessing and analysis the samples can also be used and are know tothose of ordinary skill in the art.

Next, in this particular example the samples of solution S with cells Cin the holes 18 (as shown in FIG. 4) are tested using an image analyzerwith a light source 44 and a detector 46 in this particular example.Light is transmitted from the light source 44 towards the openings 30for the holes 18 in the testing plate 12 and through the solution S inthe holes 18 of the testing plate 12. The detector 46 is positioned onthe opposing side of the testing plate 12 and detects the light whichhas been transmitted through the solution S in the holes 18. Based uponthe changes in the detected light from the transmitted light,information about the characteristics of the particular samples ofsolution S can be determined in a manner well known to those of ordinaryskill in the art. In this particular example, the image analyzer is ableto determine which holes 18 contain solution S with the highestconcentration of converted substrate and consequently the highest amountof enzyme. The target in this case is to retrieve the cells C whichproduced the largest amount of enzyme. In a similar way, cells C whichproduced the largest amount of a protein or a chemical of interest couldbe identified.

Although one example of analyzing the samples of solution S in thetesting plate 12 using optics is disclosed, other methods and techniquesfor analyzing the samples, such as non-optical methods, can also beused. For example, a plate containing samples of solution S with cells Ccould be blotted onto a membrane and used for performing Western blotanalysis or alternatively, the samples S with cells C could be blottedonto substrate containing material whereby modification of the substrateis measured visually. As a result, when non-optical means are used toanalyze the samples of solution in the testing plate 12, the testingplate 12 can be made of a transparent material.

Next, in this particular example the operator retrieves the samples ofsolution S which contain the highest concentration of convertedsubstrate. The holes 18 with the solution S with the highestconcentration of converted substrate can be identified and located basedupon which set 26 of groups 24, which group 24, and which row and columnwithin each group 24 each identified hole 18 is located. One of theadvantages of the present invention is the arrangement of the holes ingroups 24 and sets 26 which enables an operator to easily identify aparticular hole 18 on the testing plate 12. Once the desired samples areretrieved, the operator can conduct further analysis on those samples inmanners well known to those of ordinary skill in the art.

Although one example of retrieving one or more of the samples ofsolution S in the testing plate 12 is disclosed, other methods andtechniques for retrieving samples can also be used. For example, ifrobotics are used to located and retrieve a particular sample, adifferent testing apparatus, such as testing apparatus 60 shown in FIG.7, could be used. The robotics would not need the holes 18 to bearranged in groups 24 and sets 26 of holes 18, although such anarrangement may even aid the robotics in identifying and retrieving thedesired sample.

According to some embodiments of the present invention, the testingplate is in the form of an assembly or substrate. For example, the platecan comprise a plurality of individual components which together make upan assembly having opposing surfaces and a plurality of through holesextending from one surface to the other. An example of the presentinvention wherein the testing plate comprises such an assembly is aplate made of a bundle of capillary tubes as shown in FIGS. 8 and 9.

As shown in FIGS. 8 and 9, a plate, substrate or assembly 70 comprises abundle of capillary tubes 72 bound together by a band 74. The throughholes of the assembly according to this embodiment are thelongitudinally-extending holes through the center of each capillarytube. The band 74 may have opposing surfaces 76 and 78, each of which issubstantially planar and substantially parallel to the other. The bandcan be made of metal, plastic, glass, rubber, elastomeric compound, orany other suitable material. Each capillary tube 72 has a first end 80and a second end 82. The first ends 80 of the capillary tubes make up anopposing surface 84 of the substrate or assembly 70 and the second ends82 of the capillary tubes 72 made up an opposing surface 86 of thesubstrate or assembly.

As can be seen in FIGS. 8 and 9, each capillary tube 72 of the bundlewhich makes up substrate or assembly 70 has a length between its firstend 80 and its second end 82 which is at least two times greater thanthe average diameter of each tube. Preferably, the length of each tubeis more than four times greater than the average diameter of each tubeand is preferably many times greater than the average diameter. Eachcapillary tube may be, for example, in the form of a microcapillary tubeor a hollow fiberoptic fiber.

The capillary tubes may be hollow cylindrical in shape or may have otherrounded, oval, or polygonal cross-sections. The average diameter of eachcapillary tube preferably ranges from about 0.001 millimeter to about 1millimeter, and the length of each tube preferably ranges from about 1mm to about 1 cm. The dimensions of the capillary tubes are preferablysuch that each tube has the capacity to hold from about 0.0001microliter to about 10 microliters of liquid sample, for example, about5.5 microliters, although the diameters, lengths, and holding capacitiesof the capillary tubes may vary as needed or desired. According to someembodiments of the present invention, it is not necessary to have a bandfor holding the capillary tubes together in a bundle as the tubes mayinstead be fused or otherwise bonded, adhered, or maintained together ina bundle.

The number of capillary tubes of the embodiment in FIGS. 8 and 9 ispreferably from about 100 to over 1,000 capillary tubes, for example,from about 500 to about 1,500. Preferably, the tubes are arranged inrows and preferably the rows are arranged in columns. Although in theembodiment shown in FIGS. 8 and 9 the bundle of capillary tubes 72 has acircular cross-section and the band 74 is ring shaped, other shapes ofthe bundle and band are also within the scope of the present invention.For example, a rectangular or square array of capillary tubes can beprovided and surrounded by a band, and the band would also preferably beof rectangular or square shape. With rectangular or square-shaped arraysof capillary tubes, distinct columns and rows of capillary tubes can beeasily identified, facilitating the identification of a single capillarytube within the array.

In embodiments such as the one shown in FIGS. 8 and 9, the band 74surrounding the bundle of capillary tubes has a length between opposingsurfaces 76 and 78 that is greater than the length between the opposingends 80 and 82 of the capillary tubes. As a result, the banded assemblycan be placed on a surface of, for example, an analytical device,without the ends of the capillary tubes touching the surface. Inaddition, the assemblies can be stacked without disturbing the capillaryholding forces in the through holes.

The assembly shown in FIGS. 8 and 9, as with the plates of FIGS. 1-7,can be loaded or filled with a starting liquid sample to provide aplurality of samples, each constituting a portion of the starting liquidsample. Alternatively, the assembly can be loaded with more than onestarting liquid sample, with each starting liquid sample filling atleast one of the through holes. Herein, by “loaded” or “filled”, what ismeant is at least partially filled, but not necessarily fully filled.The through-holes can be loaded or filled, for example, by immersing theassembly or plate in a liquid sample, contacting at least one of theopposing surfaces of the assembly or plate with a liquid sample, orcontacting the inner walls of the respective through holes with a liquidsample or with respective liquid samples.

Contact between a liquid sample and an opposing surface can be made byflooding, immersing, pipetting, dropping, pouring, or otherwise loadingor at least partially filling a plurality of the capillary tubes orthrough holes such that capillary action pulls portions of the liquidsample into the respective capillary tubes or through holes. Uponremoval or discontinued contact of the liquid sample with the assemblyor plate, the opposing surfaces of the assembly or plate are preferablymade free of liquid sample such that the portions of the sample thatremain held within the respective capillary tubes are isolated from oneanother.

Automated filling devices can be used and are preferred if it isimportant that the respective liquid samples or liquid sample portionsare to only contact the inner walls of the through holes and avoidcontacting the opposing surfaces of the assembly.

According to embodiments of the present invention, a high throughputscreening method is provided. The method can screen for at least oneliquid sample that includes a target component or substance to beanalyzed. Herein, the target component or substance to be analyzed maybe referred to as an “analyte”. The analyte may be, but is notnecessarily, a biological sample. The analyte exhibits a detectableproperty or produces a detectable characteristic in the presence of orupon reaction with a marker compound or the like. For example, theanalyte may itself exhibit a fluorescent property. After the liquidsample is at least partially filled into a plurality of the throughholes, the portions of the liquid sample that contain the analyte can bedetected by determining which of the through holes contains a sampleportion that exhibits the fluorescent property.

In another example, the analyte itself does not exhibit a detectableproperty but may instead cause a marker component to exhibit adetectable property upon reaction with the marker component. Accordingto such an embodiment, the through holes of the testing assembly can bepre-loaded or post-loaded with one or more marker components such thatafter loading the liquid sample into the plurality of through holes, thesample portions containing an analyte can react with the marker compoundand thus enable the marker compound to exhibit a detectable property. Insuch a case, it is not the analyte itself that exhibits the detectableproperty, but rather the analyte is detected indirectly as the presenceof the analyte causes the detectable property of the marker componentwhich in turn is directly detected. In so doing, the methods of thepresent invention provide a way to partition and isolate analytes froman original liquid sample.

According to the high throughput screening method, portions of theliquid sample are loaded into a testing assembly having a pair ofopposing surfaces and a plurality of through holes, with each of thethrough holes extending from one of the opposing surfaces to the otherof the opposing surfaces. Loading preferably results in at leastpartially filling a plurality of the through holes with at leastportions of the liquid sample, and surface tension holds the respectiveportions in the respective plurality of through holes. Multiple liquidsamples can instead be loaded into respective through holes or intorespective pluralities of through holes. The method then involvesdetecting which of the plurality of sample portions in the through holesexhibit the detectable property.

According to embodiments of the present invention, the high throughputscreening assembly preferably comprises at least about 100 throughholes, more preferably at least about 500 through holes, and accordingto some embodiments of the present invention, up to about 1,000,000through holes. High throughput screening methods can be used inconjunction with these devices to test over 100,000,000 samples orsample portions per assembly per day.

The analyte to be screened may be, for example, a biological cell, amixture of biological cells, a mutant cell, a secretable protein, anenzyme, a microorganism, a mixture of microorganisms, a contaminant, orcombinations thereof. The analyte can be a population of random mutantsof one or more organisms. If the analyte is a mixture of biologicalcells it could be a random sample isolated from a natural environment.The detectable property may be, for example, a fluorescence oradsorption property. Prior to filling the high throughput assembly, theliquid sample may be diluted with a suitable diluent to obtain aconcentration of the analyte in the liquid sample such that when thesample is filled into the plurality of through holes, at least one ofthe analytes is introduced into from about one-quarter to about one-halfof the plurality of through holes.

In some cases, it is possible to identify an organism with desirableproperties even if the organism is introduced into a plurality ofthrough holes as a mixture with other organisms. Under such conditions,the mixture of other organisms, e.g., mixture of biological cells, maybe diluted prior to filling such that several organisms or cells will beintroduced into each through hole. Using such a dilution technique, itis possible to detect the presence of an analyte. For example, it ispossible to detect one particular mutant from a collection of manybiological cells and mutants thereof despite having many cells from themixture present in each through hole. Thus, for example, if a samplecontains 1,000,000 cells and only one of them is a target mutant cell,referred to as the “analyte”, and a testing plate having 10,000 throughholes is employed, the sample can be diluted such that the 1,000,000cells fill the through holes with sample portions wherein each portioncontains about 100 cells. In cases where the detectable characteristicof the analyte is detectable despite the presence of many other cellswithin the same through hole, it is possible to isolate the analyte from99.99% of the sample in a single assay.

The testing plates used in accordance with the present invention,including the plates of FIGS. 1-7 and the assemblies of FIGS. 8 and 9,can comprise hydrophilic materials or coatings, hydrophobic materials orcoatings, or a combination thereof to facilitate loading of liquidsample portions into the through holes. For example, the opposingsurfaces of the assembly can be made of, or treated with, a hydrophobicmaterial such that liquid samples tend to be repelled from the surfaceexcept in areas immediately adjacent the through hole openings on theopposing surface. According to such an embodiment, liquid sampleportions can be drawn into the through holes by capillary action withoutwetting-out onto the opposing surfaces of the plate. As a result, oncethe plate is loaded with and separated from a liquid sample no fluidcommunications are provided between individual through holes andcontamination of the partitioned sample portions is minimized. Accordingto some embodiments of the present invention, the through holes caninclude inner walls made of, or coated with, a hydrophilic material thatcan be easily wetted by an aqueous sample or medium. The entire innerwalls of each through hole can be made of or treated with a hydrophilicmaterial or only portions of the inner wall can be so made or treated.Plates having hydrophilic inner walls for the through holes andhydrophobic opposing surfaces provide excellent means to restrain,isolate, or limit the position of liquid samples in the through holes ofthe testing plate while keeping adjacent surface regions of the opposingsurfaces substantially free of liquid sample.

According to some embodiments of the present invention, to facilitatethe capillary reaction, it may be desirable to provide a hydrophilicmaterial immediately adjacent the opening to each through hole on anopposing surface while maintaining or providing the remaining area ofthe opposing surface hydrophobic or non-hydrophilic. Either or bothopposing surfaces of the testing plate can be made of or treated withhydrophobic, hydrophilic, or both materials as discussed above althoughif the through holes are to be loaded by an immersion technique, it ispreferred that the opposing surface which will come in contact with theliquid sample is treated with or formed of a hydrophobic material exceptin areas immediately adjacent and preferably surrounding the throughhole openings in the opposing surface.

Exemplary high throughput screening methods that can be used with theassemblies and other plates of the present invention include absorbancetranscription assays, fluorescent transcription assays, fluorescentsecreted enzyme assays, and microorganism screening assays. These andother suitable assays that can benefit from the plates and methods ofthe present invention are described, for example, in: Arndt et al., Arapid genetic screening system for identifying gene-specific suppressionconstructs for use in human cells, Nucleic Acids Res., 28 (6): E15(2000); Rolls et al., A visual screen of a GFP-fusion library identifiesa new type of nuclear envelope membrane protein, J. Cell Biol, 146 (1):29-44 (1999); Sieweke, Detection of transcription factor partners with ayeast one hybrid screen, Methods Mol. Biol., 130: 59-77 (2000); and WO97/37036, all of which are herein incorporated in their entireties byreference.

Having thus described the basic concept of the invention, it will berather apparent to those skilled in the art that the foregoing detaileddisclosure is intended to be presented by way of example only, and isnot limiting. Various alternations, improvements, and modifications willoccur and are intended to those skilled in the art, though not expresslystated herein. These alterations, improvements, and modifications areintended to be suggested hereby, and are within the spirit and scope ofthe invention. Accordingly, the invention is limited only by thefollowing claims and equivalents thereto.

What is claimed is:
 1. A system, comprising: a substrate comprising: afirst surface facing in an upward direction; a first recessed portionrecessed into the substrate from the first surface; an opposing secondsurface disposed below the first surface; a second recessed portionrecessed into the substrate from the second surface; and a plurality ofthrough holes extending from the first recessed portion to the secondrecessed portion, the through holes being sized to provide sufficientsurface tension to hold respective portions of a liquid sample; and afirst plate disposed over the first recessed portion, the first platesecured to the first surface of the substrate; wherein the first surfaceof the substrate spaces the first plate away from the through holes in adirection normal to the first surface.
 2. A system, comprising: a firstplate comprising: a first surface facing in an upward direction; anopposing second surface; and a plurality of through holes extending fromthe first surface to the second surface, the through holes being sizedto provide sufficient surface tension to hold respective portions of aliquid sample; a second plate disposed over the through holes andsecured to the first surface of the first plate; and a plurality ofspacers that space the second plate away from the through holes in adirection normal to the first surface.
 3. The system of claim 1, furthercomprising a liquid sample, the through holes holding respectiveportions of the sample liquid by surface tension.
 4. The system of claim1, a second plate disposed under the second recessed portion, the secondplate secured to the second surface of the substrate, wherein the secondsurface of the substrate spaces the second plate away from the throughholes in a direction normal to the second surface of the substrate. 5.The system of claim 4, further comprising a liquid sample, the throughholes holding respective portions of the sample liquid by surfacetension, wherein the first plate and the second plate are secured to thesubstrate so as to prevent evaporation of the sample liquid from thesubstrate.
 6. The system of claim 1, wherein the first plate is securedto the first surface of the substrate by at least one of a clamp, abolt, or a mechanical means.
 7. The system of claim 1, furthercomprising a light source, a detector, and optics that together areconfigured to analyze a liquid sample disposed within the system.
 8. Thesystem of claim 2, further comprising a liquid sample, the through holesholding respective portions of the sample liquid by surface tension. 9.The system of claim 2, further comprising a third plate disposed underthe through holes and secured to the second surface of the first plate,wherein the plurality of spacers space the third plate away from thethrough holes in a direction normal to the second surface.
 10. Thesystem of claim 9, further comprising a liquid sample, the through holesholding respective portions of the sample liquid by surface tension,wherein the second plate and the third plate are secured to the firstplate so as to prevent evaporation of the sample liquid from the firstplate.
 11. The system of claim 2, wherein the second plate is secured tothe first surface of the first plate by at least one of a clamp, a bolt,or a mechanical means.
 12. The system of claim 2, further comprising alight source, a detector, and optics that together are configured toanalyze a liquid sample disposed within the system.
 13. A system,comprising: a testing apparatus comprising: a first surface facing in anupward direction; a first recessed portion recessed into the testingplate from the first surface; an opposing second surface disposed belowthe first surface; a second recessed portion recessed into the testingplate from the second surface; and a plurality of spatially separatedreaction regions configured to hold respective portions of a liquidsample; a first plate disposed over the first recessed portion, thefirst plate secured to the first surface of the testing plate; andwherein the first surface of the testing apparatus spaces the firstplate away from the reaction regions in a direction normal to the firstsurface.
 14. The system of claim 11, further comprising a liquid sample,the reaction regions holding respective portions of the sample liquid.15. The system of claim 11, a second plate disposed under the secondrecessed portion, the second plate secured to the second surface of thetesting apparatus, wherein the second surface of the testing apparatusspaces the second plate away from the reaction regions in a directionnormal to the second surface of the testing apparatus.
 16. The system ofclaim 15, further comprising a liquid sample, the reaction regionsholding respective portions of the sample liquid, wherein the firstplate and the second plate are secured to the testing apparatus so as toprevent evaporation of the sample liquid from the testing apparatus. 17.The system of claim 11, wherein the first plate is secured to the firstsurface of the testing apparatus by at least one of a clamp, a bolt, ora mechanical means.
 18. The system of claim 11, further comprising alight source, a detector, and optics that together are configured toanalyze a liquid sample disposed within the system.